Estimate the proportion of the variance attributable to between-machine vs. within-machine variability?

Hypertension

Automated blood-pressure measuring devices have appeared in many banks, drugstores, and other public places. A study was conducted to assess the comparability of machine readings vs. readings using the standard cuff [13]. Readings were taken using both the machine and the standard cuff at four separate locations. The results are given in Table 12.31. Suppose we want to test whether the mean difference between machine and standard cuff readings is consistent over the four locations (i.e., if the bias is comparable over all four locations).

Table 12.31: Mean SBP and difference between machine and human readings at four locations

 

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SBP machine - SBP standard cuff (mm Hg) SBP machine (mm Hg) SBP standard cuff (mm Hg) sd Moan Location Mean sd Mean sd 142.5 142.0 18.1 23.2 98 84 98 62 98 98 84 98 21.0 22.5 0.5 0.5 14.0 11.2 12.1 11.7 13.6 134.1 147.9 135.4 133.6 133.9 128.5 84 20.3 16.7 98 62 18.3 19.0 62 6.9